The invention relates to a compressed air supply device for a utility or commercial vehicle, having a valve housing and having an air dryer cartridge, which includes a housing.
The invention further relates to an air dryer cartridge.
Compressed air supply devices are known to provide treated compressed air to compressed air consumers in utility/commercial vehicles. Typical compressed air consumers are, for example, a pneumatic brake system or an air suspension system. A compressed air supply device combines numerous functions. One important task is that of drying and cleaning the air. For this purpose, an air dryer cartridge is provided, which contains filter devices and a drying agent. Other important tasks are those of regulating the pressure of the compressed air provided by a compressor and reliably distributing the compressed air between the different consumer circuits. These tasks are performed by valve devices which are accommodated in a valve housing, specifically a pressure regulator and a multi-circuit protection valve. Modern compressed air supply devices include, in addition to the pneumatic components, an electronic controller and electrically actuable components, for example solenoid valves, and a sensor arrangement which is connected to the electronic controller. The compressed air supply devices which are equipped in this way are also referred to as EAC (Electronic Air Control) systems.
It is generally sought for the air drying to take place in as effective and efficient a manner as possible, wherein this requires, in particular, good utilization of the volume available in the air dryer cartridge.
The object on which the invention is based is that of further developing a generic compressed air supply device and an air dryer such that the drying agent completely fills the dryer volume, and is tightly packed, at all times.
This and other objects are achieved by a compressed air supply device for a utility vehicle, having a valve housing and having an air dryer cartridge which includes a housing. A drying agent box, which is filled with drying agent, is arranged in the housing of the air dryer cartridge. The drying agent is compressable by way of an elastic device.
Advantageous embodiments of the invention are described herein.
The invention provides a drying agent box, which is filled entirely with drying agent, arranged in the housing of the air dryer cartridge. The drying agent can be compressed by an elastic device. The elastic device ensures that the drying agent, which is present as granulate, is always tightly packed such that the air to be dried is subjected in an optimum manner to the drying action of the granulate. Even in the event of operation-induced fluctuations in volume of the drying agent, the elastic device ensures that the tight packing is maintained.
This may be realized, for example, in that the elastic device is a spring which is supported on the valve housing and which presses the drying agent box into the air dryer cartridge.
It may likewise be provided that the elastic device is a spring device which is fastened to the drying agent box and which drives a compression device into the drying agent box.
It may also be provided that the elastic device is realized by a plurality of spring elements, which are fastened to the drying agent box and which are supported on a housing of the air dryer cartridge and press the drying agent box into the air dryer cartridge.
According to one particularly preferred embodiment, it is provided that the drying agent box has a base on which are arranged an outer tube piece and an inner tube piece, which are open at their side facing away from the base. A further tube piece is arranged between the outer tube piece and the inner tube piece, which further tube piece is open at its side facing toward the base and can be moved in the axial direction relative to the drying agent box by the elastic device. From the outside to the center of the air dryer cartridge, there are therefore four successive walls, formed specifically by the housing of the air dryer cartridge, the outer tube piece of the drying agent box, the further tube piece, and the inner tube piece of the drying agent box.
In this way, it is provided that the housing of the air dryer cartridge, the outer tube piece, the further tube piece, and the inner tube piece form a labyrinth through which compressed air to be dried can flow whilst undergoing three reversals in flow direction. Such a labyrinthine design serves to lengthen the air path through the drying agent. In this way, it is possible for the drying action of the air dryer cartridge to be improved, or it is possible, for an unchanged drying action, to realize an air dryer cartridge with a reduced structural height.
According to one embodiment of the present invention, it is provided that the further tube piece is fastened to the housing of the air dryer cartridge. This fastening may, for example, be realized by way of spot welding, with the connection between the further tube piece and the air dryer cartridge being sealed off by a seal in order to thereby reliably define the air path through the labyrinth. The seal may, for example, be provided in the form of a hardenable material.
According to a further embodiment of the present invention, it is provided that the further tube piece is fastened to the compression device. The compression device, which is acted on with force by a spring, is thereby driven into the drying agent box together with the further tube piece in order to thereby provide the desired compression action of the granulate.
According to a further embodiment of the present invention, it is provided that the drying agent box has a base on which is arranged a tube piece which is open at its side facing away from the base, and that the compression device is arranged within the tube piece and can be moved in the axial direction relative to the drying agent box by the elastic device. In an arrangement of this type, the air to be dried flows firstly through the region between the tube piece and the housing of the air dryer cartridge in order to then, after a flow reversal, flow centrally through the drying agent box and then out of the latter.
It may be provided that the drying agent box interacts in a sealing fashion with the valve housing by way of a radial seal. This is expedient, in particular, in so-called open systems in which the air dryer cartridge seals off directly against the valve housing.
In closed systems, in which a foot flange seals off against the valve housing, it is provided that the drying agent box interacts in a sealing fashion with a foot flange of the air dryer cartridge by way of a radial seal.
It is also expediently provided that the drying agent box is connected to the housing of the air dryer cartridge by a latching device which enables an axial relative movement of the drying agent box and housing. The enabling of the axial movement permits the relative movement, for the purpose of compressing the granulate, of the components which hold the granulate.
The invention also relates to an air dryer cartridge, in particular for use in a compressed air supply device according to the invention.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.